Lens-grinding machine.



No. 739,264. l PATENTED SEPT. 15, 19.03'.

E. M. LONG & G. W. HUWLAND. I 4

LENS '-GRINDING MACHINE. l APPLIQATION FILED Nov. 19, 1902. N MODEL. A aSHEETS-SHEET z.

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mwa. wAsHmnToN n c No. 739,264. A EATENTED SEPT. 15, 1903.

E. M. LONG & G.` W. EOWLAND.

f LENS GEINDING MACHINE.

APPLICATION FILED NOV. 19, 1902.

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ivo. 739,264.

' UNITED STATES ."Patented September 15, 1903;.

PATENT OFFICE.

ELT M. LONG AND cHAUNcEY W. HowLAND, or GENEVA, NEW YORK.

LENS-GRINDING MACHINE.

.SPECIFICATION forming part of Letters Patent N o. 739,264, datedSeptember 15, 1903.

Application filed November 19I 1902. Serial No. 131,913. (No model.)

To a/ZZ whom. t may con/cern.'

Be it known that We, ELI M. LONG and CHAUNCEY W. HOWLAND, both ofGeneva, in the county of Ontario, in the State of New York, haveinvented new and usefulImprovements in Lens-Grinding Machines, of whichthe following, taken in connection with the accompanying drawings, is afull, clear, and exact description.

This invention relates vto improvements in machines for grinding lenses,the primary object of which is to grind the edges of all classes oflenses with uniformity, accuracy, and speed.

Several distinct mechanisms are employed in diderent parts of thecombined machine, and although superlicially appearing to be remote fromeach other they all contribute to carry out this one object.

Certain forms of lenses, such as the planocircular and sphero-circulartype, in which the edge is of substantially uniform thicknessthroughout, may be easily and quite accurately ground on ordinarymachines, but in grinding the edges of elliptical lenses of any facialcontour it has been discovered that as the point of contact with thegrindstone shifts from the short to the long axis the pressure of thelens upon the stone is greater than when said contact-point is shiftingfrom the long to the short axis, and therefore the portion'of theperimiter of the lens under greatest pressure is more rapidly groundaway than the remaining portions. Furthermore, as the edges of a largemajority of such elliptical lenses are thinner on the major axis than onthe minor axis the difference of time in grinding is greatly increased.This inequality of pressure and abrasion is due to the fact that it isnecessary to provide some force for automatically holding the edge ofthe rotating lens against the stone and that as the length of radius tothe point of contact is continually changing the position of the axis ofrotation of the lens gradually moves toward and from the stone, and whenthe point of contact is shifting from the short to the long axis theforce which holds the lens to the stone is counteracted and theresistance borne entirely by this portion of the devices.

lens, whereas when the point of contact shifts from the long to theshortaxis the axis of rotation moves reluctantly with said force and theabrasion of this portion of the lens is comparatively light.

Cylindrical lenses in a majority of cases are provided with their majoraxes corresponding with their optical axes if concave and with theoptical axes at right angles with their major axes if convex, so thatthe same effect is produced as previously described. Our purpose,therefore, is to provide means to compensate for this inequality on thegrinding effect upon the lenses by forcing certain portions of the lensagainstthe stone with greater pressure than other portions.

Another object is to move the grindstone axially or across the edge ofthe rotatinglens instead of moving lthe lens across the face of thestone, because it has been found to be more practicable and grinds thelens with a steadier action, since all the necessary movements'are notthen concentrated in the lenssupport, the special purpose being toprovide a constant and uniform speed in the reciprocal movement of thestone.

A still further object is to provide a suitable annunciator to enablethe attendant to ascertain without inspection whenv the lens issufficiently ground or sized, thereby saving time and obviating thenecessity for carefully watching the grinding process.

In the drawings, Figure 1 is a perspective `view of a lens-grindingmachine embodying the various features of our invention. Fig. 2 is anend view of the'lens-holding frame and the mechanism for equalizing thepressure of the lens against the stone. Figs. 3 andeare sectional viewstaken, respectively, on lines 3 3, Fig. 2, andlt 4., Fig. 3, showing inconnection with Fig. 4 the grindstone-shaft and the means for movingsaid shaft axially. Fig. 5 is a top plan of the mechanism for moving thegrindstone axially and for transmitting motion from the grindstone-shaftto the intermediary shaft which drives the lens-holding Fig. 6 is a viewsimilar to Fig. 2, showing the detached pressure equalizing device in adifferent position. Fig. 7 is a sectional View on line 7 7, Fig. 4. Fig.8 is a per- IOO spective view of the lower end of the oscillating frameand oscillating pawl. Fig. 9 is a sectional view on line 9 9, Fig. 2.

Similar reference characters indicate corresponding parts in all theviews.

In carrying out the objects of this invention agrindstone 1 is fixed tothe intermediate portion of a rotary shaft 2, which in turn is journaledin suitable bearings 3 and is also movable axially in said bearings tomove the stone across the edges of the lenses. These bearings arepreferably mounted upon a main supporting-frame 4 at opposite sides ofthe stone and are movable on ways 5 toward and from the lens-support tocompensate for varying distances of the face of the stone from thelens-holder presently described. Rotary motion is imparted to the shaft2 and stone 1 from any desired source of power, which is connected tothe fixed pulley 6 on the outer end of the shaft 2 at the left of thestone, as seen in Fig. 3. The opposite or right-hand end of the shaft 2extends beyond the adjacent bearing 3, is provided with a worm 7, andalso carries a shell or housing 8, which is pivotally hung upon theshaft 2 and incloses the worm 7 and vsuitable mechanism for transmittingaxial or reciprocal motion from the worm 7 to the shaft 2 andgrindstoneland also formsa convenient bearingfor one end of anintermediary driving-shaft 9. This shaft 9 is journaled in the front andrear walls of the housing 8 at substantially right angles to the shaft 2and is provided with a gear 10, which meshes with the worm 7 and bywhich the shaft 9 is rotated, the worm 7 being secured to the shaft 2 tomove axially therewith. A second worm 11 is mounted on the shaft 9 atone end of the gear 10 and is locked to said gear by a key 12, which isalso seated in a keyway 13 in the shaft 9 and locks both the gear 10 andworm 11 to rotate with the shaft 9 and at the same time permits saidparts to move axially with reference to each other. rlhe worm 1.1 mesheswith and rotates a second gear 14, which is mounted upon a spindle 15within the housing 8 and substantially parallel with the shaft 2, thegear 14 being provided with a hub having a diagonal groove or cam 16 inits periphery, and the worm 7 is also formed with an annular groove 17,said grooves receiving rollers 18, which are mounted upon the oppositeends of an oscillating lever 20, whereby axial and reciprocal movementis imparted to the worm 7 and shaft 2 to move the stone across the edgesof the lenses.

It has thus far been shown that the power derived from the rotation ofthe grindstoneshaft is utilized to shift it axially, and it will beapparent from the following description that this same power is alsoapplied to rotate the lens-clamps through the medium of the shaft 9.

Mounted upon suitable ways 21,which form a part of the main frame 4 andare parallel with the ways 5, is a sliding support 22, havingupwardly-projecting bearings 23, and journaled in these bearings is ashaft 24, to which rotary motion is transmitted from the shaft 9 throughthe medium of gears 25 and 26 and a clutch 27, the gear 25 being securedto the adjacent end of the shaft 24, and the gear 26 is loosely mountedon the shaft 9. The clutch 27 is also mounted on the shaft 9 andcomprises a fixed collar 28 and a sliding grooved collar 29, the lattercollar having a stud 30, which slides in an aperture 30' in the formercollar and is movable into and out of recesses 31 in the adjacent endface of the gear 26, whereby the shaft 9 may continue to rotate with orWithout the gear 26. This end of the shaft 9 is journaled in a swingingbracket 32', which is loosely mounted upon the outer adjacent end of theshaft 24, so that the support 22 or grindstone 1 may be readily adjustedtoward and from each other without cramping the shaft 9 in its bearings.

An oscillatory frame 33 is loosely mounted upon inwardly-projecting endsof the bearings 23 to oscillate concentrically with the shaft 24, andthis frame is also provided with upwardly-projecting bearings 34, 35,and 36, the bearing 34 receiving and supporting a revoluble spindle 37,and the bearings 35 and 36 receive and support suitable sleeves 38 and39, which in turn receive and support a second revoluble spindle 40,having its axis coincident with the spindle 37.

The spindles 37 and 40 are parallel with the shaft 24 and are rotatedsimultaneously at the same rate of speed, the inner or adjacent endsbeing provided withlens-clampingheads 41 and 42, .between which one or aplurality of lenses 43 may be firmly held and rotated against thegrindstone, it being understood that the spindles 37 and 40 aresubstantially parallel with the axis of revolution and face of thegrindstone. Oneof the spindles, as 37, is fixed from endwise movement,while the opposite spindle, carrying the head 42, is movable axially topermit the insertion or removal of the lenses and to hold them firmly inplace during the operation of grinding. In order to effect this axialmovement of the spindle 40, the sleeve 38 is fixed from rotary or axialmovement in the bearing 35 bya pin 44, and its outer end is enlarged andthreaded interiorly and receives an exteriorly-threaded rotary coupling46, which in turn is secured at its outer end to a rotary hand-drum 47,telescoping with the outer end of the sleeve 38 .and rotatableindependently of the spindle 40.

A sleeve 45 encircles the spindle 40, one end being flanged outwardly,and is seated loosely against the end wall of the handpiece 47, While asecond loose sleeve 45 encircles the sleeve 45, and itsinner end isflangedinwardly, a spring being interposed between the sleeves with itsopposite ends abutting against their end flanges. A xed shoulder IOO IIO

47 on the spindle 40 is interposed between a flange 48 on the coupling46 and a hardened ring 49, which is tightly tted to the spindle, andbetween this ring 49 and a similar loose hardened ring 5l is anend-thrust ball-bearing 52, the spring 50 acting to hold the inner endof the sleeve against the ring 5l, and thus holds the spindle axiallyunder yielding pressure, and the ball-bearing 52 serving to reduce thefriction, a similar end-thrust bearing 53 being interposed between thehead 4l and its bearing 34 for the same purpose. Rotary motion isimparted to the spindle 40 through the medium of the gear 25 and anintermeshing gear 54, which is feathered upon said spindle to rotate thesame and at the same time permit the spindle to be moved axially.

The opposite spindle 37 is rotated in the same direction as the spindle40 by means of intermeshing gears 55 and 56, which are secured,respectively, to the shaft 24 and spindle 37, and it is now apparentthat although the grindstone may rotate continuously the rotation of thelens-holders may be stopped and started at the will of the operator bymeans of the clutch 27 and that the clampinghead 42 may he moved axiallyby simply ro-4 tating the drum 47. p

The rotation of the lens-holders is preferably stopped automaticallywhen the oscillating frame 33 isrocked backwardly in the act ofwithdrawing the lenses from vcontact with the stone and particularlywhen the grinding operation is completed, and for this purpose the frameis provided with a lug 57, depending beneath its axis and arranged toengage one end of a lever 58, which is fulcrumed at 59, and its otherend is provided with a roller 60, riding in the annular groove of thecollar 29, as best seen in Figs. l, 4, and 8, a suitable catch 6l beingconnected to the Oscillating frame for engaging a lug 62 on the slidingbed and holding said oscillating frame in its inoperative position.

The means for sizing and forming the lenses consists of a former 63 anda bell-crank Vlever 64, carrying a contact-piece 65, the

former 63 being of the same outline as desired for the lens to be groundand is removably secured to the outer end of the spindle 87 by asuitable clamping-screw 66 and pins 67, and the lever 64 is fulcrumed inan upright position at 68 to bearings 69 on the sliding support 22 andis adapted to be rocked to change the position of the contact-piece 65relative to the axis of the former for varying the size of thelens whendesired.

The means for adjusting the lever 64 preferably consists of a threadedstud 70 and a graduated rotary nut or threaded disk 7l,A

mounted on the threaded stud and havingits graduations adapted toregister with an indicator-disk 72, the stud 70 being secured to thesupport 22 and projecting upwardly through a slot in one arm of thelever 64, and the disk 72 rests upon and is'locked to the upper face ofsaid arm by a pin 73, which enters an aperture in the lower wall of'saiddisk lto thereby adjust the position of the contact-V piece 65.

In order to compensate for the inequality in pressure and consequentunequal abrasion or grinding of the lens during the process of grindingthe same, an eccentric 76 is provided upon the shaft 24, which shaft isgeared to rotate at twice the speed of the spindles 37 and 40, and thiseccentric is connected by a pitman 77 to an upright lever 78 at a pointabove its fulcrum, the upper end of the lever being connected by aspring 79 to the oscillating frame 33 at a point above its axis. centricis positioned with reference to the long and short axis of ellipticallenses, so that the tension of the springis gradually increased fromminimum to maximum while the contact-point of the lens with the stone isshifting from the long to the short axis, and this tension is graduallydiminished while the point of contact is changing from the short to thelong axis. It is therefore apparent that While the spring is beingtensioned the lens is being pressed with greater force against the stoneand grinds away the lens more rapof contact while passing from the longto the short axis, While, on the other hand, when the contact isshifting from the short to the longV axis, during which the resistancedue to the gravity of the oscillatory frame, which is usually augmentedby a spring, is borne entirely by the lens, and during this time theeccentric causes a relaxation in the tension of the spring, andtherefore tends to grind the lens undera more uniform pressure through-Aout its perimeter.

The upright lever 78 is usually fulcrumed The ecidly to compensate forthe natural reluctance l on a support 80, which is adjustably secured inone of the ways 5, so that the parts of this compensating mechanism maybe adjusted to a nicety,and although the utility of this mechanism hasbeen specifically described for grinding elliptical lenses it will beobvious to any one skilled in the art that it is equally applicable forgrinding cylindricallenses, whether circular or elliptical, in which theedges to be ground are thinnest on the optical axis corresponding tothelong axis of the plano or spherical elliptical lenses or on the axisat right angles with the optical axis. n

The bearing-face of the contact-piece 65 is curved toconform as nearlyas possible to` lens. This contact-plate is preferably formed f ofelectric conducting material and insulated from thelever and, togetherwith the former, is connected in circuit with an annunciator,

IIS

as a bell 81, the object of this being that as soon as the lens isground to the desired size throughout its perimeter the circuit will beclosed continuously through contact of the former with the plate 65, andthe attendant is then informed of this fact through the continued actionof the bell or other annunciator.

I-Iaving thus described our invention, what We claim, and desire tosecure by Letters Patent, is

1. In a lens-grinding machine, the combination with a grinder, of arotary lens-holder, a spring connected to move the lens-holder towardthe grinder, and automatic means to 'vary the tension of the spring toproduce a uniform grinding eifect upon the lens.

2. In a lens-grinding machine, the combination With a grinder, of arotary lens-holder, a spring connected to move the lens-holder towardthe grinder, a-nd automatic means to increase the tension of the springwhen the grinding effect on the lens tends to be reduced.

3. In a lens-grinding machine, the combination with a grinder, of arotary lens-holder, a spring connected to move the lens-holder towardthe grinder, and automatic means to reduce the tension of the springwhen the grinding effect on the lens tends to increase.

4. In a lens-grinding machine, the combination with a grinder, of arotary lens-holder having independent movement toward and from thegrinder, a spring connected to move the holder toward the grinder, andautomatic means separate from the holder to vary the tension of thespring.

5. In a lens-grinding machine, the combination With a grinder, of arotary lens-holder having independent movement toward and from thegrinder, a spring connected to move the holder toward the grinder, amovable member separate from the holder and connected to the spring, andautomatic means to;

move said member.

6. A machine for grinding elliptical lenses comprising agrinding-surface and a rotary lens-holder, one of the parts beingmovable automatically toward the other to bring the edge of the lens andsaid surface into contact, and automatic means to increase the pressureof said contact as it shifts from the long to the short axis.

7. A machine for grinding oval lenses comprising a grinding-surface, arotary lensholder movable automatically toward said surface to contactthe edge of the lens therewith, and automatic means acting on thelensholder to increase the pressure of said contact as it shifts fromthe long to the short axis.

8. A machine for grinding oval lenses comprising a grinding surface, arotary lensholder movable automatically toward said surface to contactthe edge of the lens therewith, and automatic means acting on thelensholder to increase the pressure of said contact as it shifts fromthe long to the short axis, said means acting to reduce the pres'.- sureof the contact as it shifts from the short to the long axis.

9. A machine for grinding oval lenses comprising a grinding surface, arotary lensholder gravitating toward said surface to contact the edge ofthe lens therewith, a spring connected toforce the holder toward thegrinding-surface, and automatic means to gradually tension the spring asthe contact is shifting from the long to the short axis.

10. Amachineforgrindingovallensescomprising a grinding surface, a rotarylensholder gravitating toward said surface to contact the edge of thelens therewith, a spring connected to force the holder toward thegrinding-surface and an eccentric connected and operating to tension thespring as the contact shifts from theI long to the short axis.

l1. A machine for grinding lenses, the combination with agrinding-surface,`of a rotary lens-holder, and means to move the holderto contact the edge of the lens With the grinding-surface, and automaticmeans to increase the pressure of the contact as it shifts from theopposite ends of its long axis.

12. In a machine for grinding lenses, a rotary grindstone-shaft and arotary lens-holder, a lever operatively connected to move thegrindstone-shaft endwise, and a second shaft driven by thegrindstone-shaft and operatively connected to rotate the lens-holder andto actuate the lever.

13. In a machine for grinding lenses, arotarygrindstone-shaftandarotarylens-holder, a rocking support for thelens holder, a bracket pivoted axially with the support, a housingpivoted axially with the grindstoneshaft, a second shaft journaled inthe bracket and housing and operatively connected to be driven by thegrindstone-shaft and to move the same axially, said second shaft beingalso operatively connected to rotate the lensholder.

14. In a machine for grinding lenses, a rotarygrindstone-shaftandarotarylens-holder, a gear-case mounted on the shaft, a second shaftjournaled in the gear-case, intermeshing gears secured to said shafts,additional intermeshing gears Within the case one of which is secured tothe second shaft, and a lever Within the case actuated by the one of theadditional gears and operatively connected to move the grindstone-shaftendwise.

15. In a lens-grinding machine, a grindstone-shaft, in combination withtwo intermeshing gears, one being secured tothe shaft, two additionalintermeshing gears driven by the former gears, one of the latter gearshaving a spiral groove, and a lever having one end riding in the grooveand its other end operatively connected to move the grindstoneshaftendwise. i

i6. The combination with a rotary lensholder, of a rotarygrindstone-shaft movable axially tc move the grindstone across the edgeof the lens, and a second shaft driven IOO IIO

by the former shaft and connected to transmit rotary motion to thelens-holder.

17. The combination, with a rotary lensholder, of a rotarygrindstone-shaft movable axially to move the grindstone across the edgeof the lens, a second shaft driven by the former shaft, connections fortransmitting rotary motion from the second shaft to the lens-holder, andmeans to make and break said connections.

18. In a lens-grinding machine, a rotary lens-holder and a rockingsupport therefor, driving mechanism for the lens-holder in-v cluding aclutch to throw the driving mechanism into and out of connection withthe lens-holder, and means actuated by the rocking support when moved inone direction to throw the clutch from one position to another.

19. In a lens-grinding machine, the combination with a grindstone, asupport movable toward and from the grindstone, a rotary lensholder onthe support, driving mechanism for the lens-holder including a clutchfor disconnecting the driving mechanism, and means actuated by thesupport when moved from the grindstone for throwing the clutch out ofaction.

20. In a lens-grinding machine, the combination with a grinder, ofseparate rotary spindles having lens clamping heads, a fixed sleeve, arotary handpiece encircling one of the spindles and operativelyconnected to a fixed sleeve and to the inclosed spindle to move itselfand the spindle which it encircles axially.

21. In a lens-grinding machine, the combination with a grinder, ofseparate rotaryspindles having lens clamping heads, a lixed sleeve, arotary handpiece encircling one of the spindles and itself and thespindles which it encircles axially, and a spring between the axiallymovable spindle and handpiece whereby the lens is held between the headsunder yielding pressure.

22. In a lens-grinding machine, the combination with a grinder, ofSeparate rotary spindles having lens-clamping heads, a rotary handpieceencircling one of the spindles and operatively connected to move itselfand the spindle which it encircles axially, a shoulder on theaxially-movable spindle, an antifriction end-thrust bearing adjacent theshoulder, and a spring between the bearing and handpiece for the purposeset forth.

23. In a lens-grinding machine, the combination with a grinder, ofseparate rotary spindles having lens-clamping heads, a fixed threadedsleeve and a rotary threaded handpiece both encircling one of thespindles and engaged with each other, the handpiece being operativelyconnected to move the spindle which it encircles endwise, and a springbetween the axiallymovable spindle and handpiece for the purpose setforth.

24. In combination with a grinding-surface and a rotary lens-holder, aformer connected to and rotating with the lens-holder, a lever and acontact-piece mounted thereon, a fixed threaded stud, an indicator-diskconcentric with the stud and fixed from rotation to the lever, and agraduated nut engaged with the threaded stem whereby the rotation of thenut on the stud operates to rock thelever for shifting the position ofthe contact-piece and indicating the size of the lens to be ground.

In witness whereof we have hereunto set our hands this 14th day ofNovember, 1902.

ELI M. LONG. CHAUNCEY W. HOWLAND.

Vitnesses:

L. W. KEYES, E. S. BOYDEN,

